<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        .progress {
            height: 25px;
            width: 400px;
            border-radius: 15px;
            background-color: #272425;
            border: 3px solid #272425;
            box-sizing: border-box;
            margin-bottom: 30px;
        }
        .inner {
            width: 50%;
            height: 20px;
            border-radius: 10px;
            text-align: right;
            position: relative;
            background-color: #409eff;
            background-size: 20px 20px;
            box-sizing: border-box;
            transition: all 1s;
        }
        .inner span {
            position: absolute;
            right: -20px;
            bottom: -25px;
        }
    </style>
</head>
<body>
<div id="app">
    <div class="progress">
        <div class="inner" :style="{width: percent+'%'}">
            <span>{{ percent }}%</span>
        </div>
    </div>

    <button @click="percent = 25">设置25%</button>
    <button @click="percent = 50">设置50%</button>
    <button @click="percent = 75">设置75%</button>
    <button @click="percent = 100">设置100%</button>
</div>
<script src="vue.js"></script>
<script>
    /**
     * 作用：动态设置style样式
    */
    const app = new Vue({
        el: '#app',
        data: {
            percent: 0
        },
    })
</script>
</body>
</html>